Froth flotation process



oam n. cunumensm, or rnovo,

.where duly ll Silo Drawing.

This invention relates to the recovery of minerals, such as sulfide ores and the like, by the froth flotation process and is herein described as applied; to the concentration of minerals and ores loy the use of certain ketone-condensation sulfur products as a flotation collecting reagent;

More particularly upon the discovery that a highly e'fiective flotation reagent can he obtained by the reactionof a ketone, (such, for example, as acetone) with an alkali metal hydroxide and carbon disulfide; this reaction yielding a compound or compounds of complex molecular structure, which is herein referred to as a ketone-condensation sulfur product.

To illustrate the type of product that may he formed by the reaction according to the invention, it is stated in the literature (Berichte der deutschen chemischen Gesellschaft, vol. 38, page 2888) that the reaction of diethyl ketone, with an alkali hydroxide and carbon disulfideyields dimethyl ketcpenthiophen dithiol of the following structure Y o t OKs-.6 E-JJHa ns- -sn \g/ and that the same type of compound is formed as the main product of reaction with any ketone of the formula R-CHyCO-OH -R (R) stands for either an or aryl group; the reaction taking place we expressed according to the following equation:--

o=o+2os,+4xo11=R-c h-n+xls+4mo n-on xs- -sx \s/ As specific examples the following methods are given for preparin the ketouecondensation sulfur product '0' the invention, but without intending to restrict the invention thereto Ema mph 1 5 parts of sodium hydroxide and 15-20 solution or was in a this invention is based ents (unreacted acetone and CS Application filed September 10, 1928. Serial No. 305,141.

parts of very pure acetone were ground together until the alkali had either gone into finely dispersed condition. To this was then added ten parts of carbon disulfide (CS and the reaction completed by grinding a little longer. The reaction mixture was allowed to stratify, and was separated into two layers. One layer consisted of an acetone-carbon disulfide solution which, on evaporating oil the solvyielded 5.2 parts of the ketone-condensation sulfur product. The other layer consisted of dark red sticky, gummy residue, weighing 7.5 parts. I I I The latter residue of the above preparation, on drying at 60 (1., set to solid UTAH, assrenoa screens 0. saints, onrunmnarenas, rnnmnn product (weight about 6.5 parts) which was shown to consist largely of sodium sulfide. Depending upon the amount of water present, the residue may be a darkred sticky solid, ora material having the appearance of tar or a mobile liquid of a reddish color.

While very pure acetone was used in this example, the commercial grades or even the relatively impure grades of acetone, of commerce may also he used. This applies also to the other ketones referred to.-

In the above example, instead of carrymg out the reaction in two steps, the re-.

acting substances (acetone,-;alkali metal hydroxide and CS may! be ground together ina one step operation, nor is the invention limited to carrying out the re action at room temperature.

cyclic vaporization and then condensation" of the acetone-carbon disulfide mixture,

process, using 6 parts of By this type of parts of acetone, and

sodium hydroxide,

bye continuous and I 20 parts of carbon disulfide, there were obv inally held the alkali metal hydroxide. the

product as a free acid the above period of about 24 hours the product of reaction in water -1norganic matter consisting largely of sodium sulfide. i

In place of sodium hydroxide, in the above example, potassium hydroxide may be used with equally good results and while proportions of reacting a substances are given as possible examp es, the invention is not limited to the use of any definite quantity of thechemicals herein named. It is preferable in practice to use (as in the above examples) an excessof the acetone to constitute a solvent.

\ Eaimple 3 Into a suitable flask was placed 10 parts of dibenzyl ketone, 25 arts of carbon disulfide and 10.8 parts of finely ground potassium hydroxide," the reaction mixture being cooled to keep the temperature of reaction at 25 C. or thereabout. Over a the reaction mixture was intermittently triturated with a flattened glass rod, the reaction being con ducted at room temperature (about 25 C.) and the reaction finally completed by heating on a steam bath for one hour at about the boiling point of carbon disulfide. The product thus obtained was freed of excess carbon disulfide and moisture present by allowing it to stand in a drying desiccator under vacuum over night; the resulting reddish crystalline product consisting of a mixture of potassium sulfide and'the ketone-condom sation sulfur product, and weighing about 27 parts.

This product may be used directly as a.

flotation reagent or it may be freed of potassium sulfide by extracting with absolute ethanol (the ketone-condensation sulfur product being very soluble in vethanol and the potassium sulfide relatively, insoluble); the reddish oily crystalline product obtained, on evaporating off the ethanol, consisting of the j potassium salt of the ketone-condensation sulfur roduct, relatively free of potassium sulfi e, and weighing 15.0-18.0 parts.

Another method of making the above separation maybe obtained-by dissolving and precipthe ketone-condensation sulfur by acidifying with dilute hydrochloric acid. The free acid ketone-condensation sulfur product thus itating separated may be used in froth flotation as the free acid or as an alkali metal salt thereof by dissolvingit in sodium or potassium hydroxide solutlon.

As a part of the whole process in the I above examples, the' allrali metal sulfide byproduct,'formed in flotation reagent, alkali again, for example by oxidizing the sulfide to sulfate and-then causticizing with lime.

The products, such as those illustrated in the above examples, were employed as collectin reagents in the flotation of a copper sul de' ore of the Utah Copper (10., analyzing about 1.0% copper, in the ratio the preparation of the may be regenerated as -of'one tenth pound (0.1 lb.) of the product per ton ofdry ore, and pine oil as a frothing reagent, and a lime circuit bein employed therewith. iThe ore was Sub ected to the ordinary flotation o eration in a mechanical agitation type of flotation machine and 'a tailing analyzing copper was obtained together with a high grade concentrate, corresponding to a recovery of about 90% of the copper value of the ore. The flotation reagent can be used. in the flotation of ores in en'eral, and larger or smaller amounts of t e reagent than above specified can also be used, depending on the type of ore and other conditions. Furthermore, the invention is not limited to any particular type of flotation cell, and instead of an alkaline circuit as used in the above example, an acid or neutral circuit can be em 10 ed. I v

n t e above specification mention is made of ketones, such, for example, as acetone and di-benzyl ketone. It is to be understood that other ketones or mixtures thereof, such as di-ethyl ketone, di-propyl ketone andhigher ketones, as well as mixed ketones such as methyl-ethyl ketone and ketones containing both alkyl and aryl residues, can be likewise employed.

Claims 1. A flotation a ketone-condensation sulfur product which can be formed from ketone and carbon bisulfide.

2. A flotation rocess in which ore is subjected to frothotation in the presence of a ketone-condensation sulfur product which can be formed from ketone and carbon bisullfide and a frothing agent such as pine o1.

3. 'A flotation process in which frothflotation of ore is conducted in an aqueous liquid carrying a small amount of a reaction product of caustic alkali, a' ketone and CS 4. A rocess of froth flotation in the presence 0 a compound having the general formula a; a. Mr L...

metal hydroxlde, and used over" about 0.10%

process in which ore is subected to froth-flotation in the presence of in which R represents hydrogen, alkyl or aryl and .M represents an alkali-forming metal or hydrogen;

5. A process which comprises froth flotation in the presence of a condensation product of an aliphatic ketone and carbon bisulfide which can be formed in the presence of an alkali.

6. A process which comprises froth flota-' tion in the presence of a condensation product of acetone and carbon bisulfide which can be formed in the presence of an alkali.

7. A process which comprises froth flotation in the presence of a ketopenthiophen dithiol and a frothing agent. i

8. A process which comprises froth flotation in the presence of a di-substituted ketopenthiophen dithiol and a frothing.

agent.

9. A process which-comprises froth flotation in the presence of a di-alk'yl ketopenthiophen dithiol'and afrothing agent. 10. A process which comprises froth-flotation in the-presence of a ketone carbon bisulfide condensation product. a

In testimony whereof I have signed *mv name to this specification.

ORIN D. CUNNINGHAM. 

